Current detection printed board, voltage detection printed board, and current/voltage detector using same, and current detector and voltage detector

ABSTRACT

A current detection printed board includes: a board having a penetration hole that penetrates the board; and at least one wire that is formed in a coiled shape having both ends by penetrating the board along the periphery of the penetration hole and alternately connecting a front surface layer and a rear surface layer of the board, wherein, when a conductor, in which an AC current flows, is disposed to pass through the inside of the penetration hole, a current flowing in the wire is output through electromagnetic induction.

This application is a continuation application of pending U.S. patentapplication Ser. No. 12/732,773, filed Mar. 26, 2010, which is acontinuation of U.S. patent application Ser. No. 11/627,703, filed Jan.26, 2007 (Now U.S. Pat. No. 7,714,594, issued on May 11, 2010) whichclaims priority under 35 USC §119 to Japanese Application No.2006-021528, filed Jan. 30, 2006 and Japanese Application No.2006-208966, filed Jul. 31, 2006, the disclosures of which are expresslyincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a current detection printed board thatis used to detect an alternating current flowing in a power transmissionconductor used as an alternating current (AC) power transmission path,to a voltage detection printed board that is used to detect an ACvoltage to be generated in the power transmission conductor, to acurrent/voltage detector using the same, and to a current detector and avoltage detector. In particular, the invention relates to a technologythat uses high-frequency power as AC power.

2. Description of the Related Art

Like an impedance matching device or a high-frequency power supplydevice, there is known a device that detects AC power current andvoltage and performs a control using the detected current and voltage.As an example, an impedance matching device will now be described.

FIG. 26 is a block diagram of an example of a high-frequency powersupply system that uses an impedance matching device.

The high-frequency power supply system is a system that performs aprocessing, such as plasma etching or plasma CVD, on a workpiece, suchas a semiconductor wafer or a liquid crystal substrate. Thehigh-frequency power supply system includes a high-frequency powersupply device 61, a transmission line 62, an impedance matching device63, a load connection portion 64, and a load 65 (plasma processingdevice 65).

The high-frequency power supply device 61 is a device that outputshigh-frequency power to the plasma processing device 65 as a load.Moreover, high-frequency power output from the high-frequency powersupply device 61 is supplied to the plasma processing device 65 throughthe transmission line 62 having a coaxial cable, the impedance matchingdevice 63, and the load connection portion 64 having a shielded copperplate. In general, the high-frequency power supply device 61 outputshigh-frequency power having a frequency of a radio frequency band (forexample, a frequency of hundreds kHz or more).

The plasma processing device 65 is a device that performs a processing(etching or CVD) on a wafer or a liquid crystal substrate.

The impedance matching device 63 includes a matching circuit that has avariable impedance element (for example, a variable capacitor, avariable inductor, or the like) (not shown) therein. The impedancematching device 63 has a control function of changing impedance of thevariable impedance element in the matching circuit to accomplishimpedance matching between the high-frequency power supply device 61 andthe load 65.

In order to perform the above-described control, a current detector anda voltage detector are provided between an input terminal 63 a of theimpedance matching device 63 and the matching circuit. The currentdetector and the voltage detector detect high-frequency current andhigh-frequency voltage output from the high-frequency power supplydevice 61. Information of forward wave power or reflected wave power isobtained using the current and voltage detected by the detectors. Then,impedance of the variable impedance element is controlled using theobtained information to accomplish impedance matching.

FIG. 27 is a schematic circuit diagram of a current detector 80 and avoltage detector 90 provided between the input terminal and a matchingcircuit 67 of the impedance matching device 63. As shown in FIG. 27, apower transmission conductor 66 (for example, rod-shaped copper) servingas a power transmission path is provided between the input terminal 63 aand the matching circuit 67. Then, the current detector 80 and thevoltage detector 90 are provided on the power transmission conductor 66.

The current detector 80 has a current transformer 81, output wires 82and 83 of the current transformer 81, a current conversion circuit 84,and an output wire 85 of the current conversion circuit 84. In thecurrent detector 80, a current according to an AC current that flows inthe power transmission conductor 66 flows in the current transformer 81.This current is input to the current conversion circuit 84 through theoutput wires 82 and 83 and is converted into a predetermined voltagelevel. Then, the converted voltage is output from the output wire 85 ofthe current conversion circuit 84.

The voltage detector 90 has a capacitor 91, an output wire 92 of thecapacitor 91, a voltage conversion circuit 93, and an output wire 94 ofthe voltage conversion circuit 93. In the voltage detector 90, a voltageaccording to an AC voltage generated in the power transmission conductor66 is generated in the capacitor 91. This voltage is input to thevoltage conversion circuit 93 through the output wire 92 and isconverted into a predetermined voltage level. Then, the convertedvoltage is output from the output wire 94 of the voltage conversioncircuit 93.

Subsequently, as described above, the information of forward wave poweror reflected wave power is obtained using the current and voltagedetected by the current detector 80 and the voltage detector 90. Thecurrent detector 80 and the voltage detector 90 have a structure shownin FIGS. 28 and 29.

FIG. 28 is a schematic exterior view of the current detector 80 and thevoltage detector 90.

FIGS. 29A to 29C are explanatory views illustrating the configuration ofthe current detector 80 and the voltage detector 90 shown in FIG. 28.Specifically, FIG. 29A is a diagram showing the interior of a casing(indicated by a dotted line) of FIG. 28 in perspective view. FIG. 29B isa diagram showing the vicinity of the current transformer 81 as viewedfrom the transverse side of FIG. 29A. FIG. 29C is a diagram showing thevicinity of the capacitor 91 as viewed from the transverse side of FIG.29A.

In FIGS. 28 and 29A to 29C, the power transmission conductor 66 and aninsulator 69 covering the power transmission conductor 66, not includedin the current detector 80 and the voltage detector 90, are shown forexplanation. Further, in FIGS. 28 and 29A to 29C, for convenience, thesame parts as those in FIG. 27 are represented by the same referencenumerals.

Hereinafter, the current detector 80 and the voltage detector 90 will bedescribed with reference to FIGS. 28 and 29A to 29C.

In FIGS. 28 and 29A to 29C, the power transmission conductor 66 is, forexample, a cylindrical copper rod. The periphery of the powertransmission conductor 66 is covered with a hollow insulator 69. Then,the power transmission conductor 66 and the insulator 69 pass through acasing 71. Further, the current transformer 81 constituting the currentdetector 80 and the capacitor 91 constituting the voltage detector 90are accommodated in the casing 71.

In the current transformer 81, a coated copper wire or the like is woundaround a ring-shaped magnetic core (for example, a toroidal core or aferrite core) to form a coiled wire. Then, the current transformer 81 isdisposed such that the power transmission conductor 66 passes throughthe magnetic core. Accordingly, a current according to a current flowingin the power transmission conductor 66 flows in the coiled wire of thecurrent transformer 81.

The current flowing in the current transformer 81 is input to thecurrent conversion circuit 84 through the output wires 82 and 83 thatare connected to both ends of the coiled wire. Then, the currentconversion circuit 84 converts the input current into a predeterminedvoltage level and outputs the converted voltage.

The capacitor 91 is formed by providing a ring-shaped conductor 91 b(for example, a copper ring) in the vicinity of the insulator 69. Thering-shaped conductor 91 b and a portion 91 a facing the powertransmission conductor 66 function as electrodes of the capacitor.Accordingly, a voltage according to the voltage generated in the powertransmission conductor 66 is generated in the capacitor 91. The voltagegenerated in the capacitor 91 is input to the voltage conversion circuit93 through the output wire 92 connected to the ring-shaped conductor 91b. Then, the voltage conversion circuit 93 converts the input voltageinto a predetermined voltage level and outputs the converted voltage.

Moreover, in FIGS. 28 and 29A to 29C, the output wire 85 of the currentconversion circuit 84 and the output wire 94 of the voltage conversioncircuit 93 are not shown. Further, in order to protect the currentconversion circuit 84 and the voltage conversion circuit 93 from aninfluence of an electromagnetic wave, a common conductor cover 72 isprovided to cover the current conversion circuit 84 and the voltageconversion circuit 93. FIG. 28 shows a state where the cover 72 isremoved, in order to show the current conversion circuit 84 and thevoltage conversion circuit 93. Further, in FIGS. 29A to 29C, the cover72 is not shown.

As described with reference to FIGS. 28 and 29A to 29C, the currentdetector 80 and the voltage detector 90 have the casing that covers thecurrent transformer 81, the capacitor 91, and the like, in addition tothe parts of the circuit diagram in FIG. 27. The casing is common to thecurrent detector 80 and the voltage detector 90 according to the relatedart.

The current detector 80 and the voltage detector 90 described above canbe used to other devices, such as the high-frequency power supply device61 or the like. For example, in case of the high-frequency power supplydevice, the current detector and the voltage detector are provided at anoutput terminal of the high-frequency power supply device 61. In thiscase, the current detector and the voltage detector are used to detectcurrent and voltage required for controlling output forward wave powerto have a set value.

The current detector and the voltage detector may detect current andvoltage at the output terminal 63 b of the impedance matching device orthe input terminal of the load 65 and may be used to control or analyzethe detected current or voltage.

FIG. 30 is a circuit diagram showing a case where the current detector80 and the voltage detector 90 are provided between the matching circuitand the output terminal in the impedance matching device.

As shown in FIG. 30, the current detector 80 and the voltage detector 90are provided on the power transmission conductor 68 between the matchingcircuit 67 and the output terminal 63 b in the impedance matchingcircuit. In this case, the current detector 80 and the voltage detector90 detect current and voltage at the output terminal 63 b of theimpedance matching circuit.

In FIG. 30, the same parts as those of the circuit diagram in FIG. 27are represented by the same reference numerals. Meanwhile, there is adifference in current and voltage at the input terminal 63 a and theoutput terminal 63 b of the impedance matching circuit. Accordingly, thecurrent detector 80 and the voltage detector 90 have a structuraldifference in view of current resistance and voltage resistance. In FIG.30, the same reference numerals are used regardless of the structuraldifference. For example, the output terminal 63 b of the impedancematching circuit has higher current and voltage than the input terminal63 a thereof. For this reason, when the current detector 80 and thevoltage detector 90 are provided at the output terminal 63 b of theimpedance matching circuit, it is necessary to extend an insulationlength, compared with a case where the current detector 80 and thevoltage detector 90 are provided at the input terminal 63 a of theimpedance matching circuit. In order to extend the insulation length, aconductor having a large diameter is used as the power transmissionconductor 68 or the insulator 69 covering the periphery of the powertransmission conductor 68 has a large thickness. In FIG. 30, however,for convenience, the structural difference is not considered.

As shown in FIG. 30, when the current detector and the voltage detectorare used in the impedance matching circuit, it is necessary toadditionally provide a detector for detecting information of current andvoltage for impedance matching on the input side of the impedancematching circuit.

-   Patent Document 1: JP-A-2003-302431-   Patent Document 2: JP-A-2004-85446

Since the current transformer 81 constituting the current detector 80 isformed by winding the wire around the magnetic core, a variation inwiring interval or wiring strength may easily occur. For this reason,when a plurality of current detectors 80 are formed, a variation indetection value of the individual current detectors 80 may easily occur.

Further, a variation in shape of the output wires 82 and 83 of thecurrent transformer 81 may easily occur, which may cause a variation incurrent detection value.

The inner diameter of the ring-shaped conductor 91 b constituting thevoltage detector 90 is substantially consistent with the outer diameterof the insulator 69 covering the periphery of the power transmissionconductor 66. The ring-shaped conductor 91 b is fitted into theinsulator 69. That is, the ring-shaped conductor 91 b is positioned bythe insulator 69. However, the insulator 69 may be thinned due to asecular change or the like. In this case, the position of thering-shaped conductor 91 b may be unstable, and a gap may occur betweenthe power transmission conductor 66 and the insulator 69. In this state,if an external force acts on the power transmission conductor 66, thepositional relationship between the power transmission conductor 66 andthe ring-shaped conductor 91 b changes. Then, a voltage detection valuechanges from an initial state (upon adjustment of the detector).Besides, since the position of the ring-shaped conductor 91 b isunstable, when a plurality of voltage detectors 90 are formed, avariation in detection value of the individual voltage detectors 90 mayeasily occur.

Further, a variation in shape of the output wire 92 of the ring-shapedconductor 91 b may easily occur, which may cause a variation in voltagedetection value.

That is, in case of the current detector 80 or the voltage detector 90,when a plurality of detectors are formed, a variation in detection valueof the individual detectors may easily occur.

Further, since the wire is wound around the core in the currenttransformer 81 constituting the current detector 80, there is aself-resonant frequency by self inductance and line capacitance.However, since relative magnetic permeability of a magnetic materialused for the core is large, the self-resonant frequency becomes low. Forthis reason, an upper limit of a detectable frequency band becomes low.That is, the detectable frequency band is limited.

In case of manufacturing the impedance matching device, when the currentdetector 80 and the voltage detector 90 are installed in the device, itis necessary to install the power transmission conductor 66 and the likesimultaneously. However, there are many cases where the impedancematching device or the like is cramped. Accordingly, it may be difficultto install the power transmission conductor 66 and the likesimultaneously due to interference with other parts. In addition, whenthe current detector 80 and the voltage detector 90 are removed formaintenance, since it is necessary to remove the power transmissionconductor 66 and the like simultaneously, it may be difficult to removethe current detector 80 and the voltage detector 90. For example, whenthe current detector 80 and the voltage detector 90 are disposed on theback side of the impedance matching device, it is necessary to removethe parts on the front side. At this time, in the configuration of therelated art, since the volume of a portion to be removed becomes large,and thus it is necessary to remove more parts. As a result, a largernumber of work steps are required.

SUMMARY OF THE INVENTION

An object of the invention is to provide a current transformer and acapacitor that can reduce a variation in current detection value orvoltage detection value of individual detectors even though a pluralityof detectors. Another object of the invention is to provide acurrent/voltage detector, and a current detector and a voltage detectorthat use the current transformer and the capacitor. Still another objectof the invention is to improve maintenance.

According to a first aspect of the invention, there is provided acurrent detection printed board comprising: a board having a penetrationhole that penetrates the board; and at least one wire that is formed ina coiled shape having both ends by penetrating the board along theperiphery of the penetration hole and alternately connecting a frontsurface layer and a rear surface layer of the board, wherein, when aconductor, in which an AC current flows, is disposed to pass through theinside of the penetration hole, a current flowing in the wire is outputthrough electromagnetic induction.

According to a second aspect of the invention, the wire may include:through holes formed at the penetrating portion of the board; andpattern wires formed on the front surface layer and the rear surfacelayer.

According to a third aspect of the invention, wherein, when a pluralityof the wires are formed in the board, both ends or electricallyidentical portions of each wire may be electrically connectable to bothends or electrically identical positions of another wire.

According to a fourth aspect of the invention, there is provided acurrent detection printed board comprising: a board having a penetrationhole that penetrates the board; and at least one wire that is formed ina coiled shape and has both ends by penetrating between a top conductivelayer and a bottom conductive layer of the board along the periphery ofthe penetration hole and alternately connecting the top conductive layerand the bottom conductive layer of the board, and/or at least one wirethat is formed in a coiled shape and has both ends by penetrating a partof layers of the board and alternately connecting a top conductive layerand a bottom conductive layer of the penetrating portion, wherein, whena conductor, in which an AC current flows, is disposed to pass throughthe inside of the penetration hole, a current flowing in the wire isoutput through electromagnetic induction.

According to a fifth aspect of the invention, the wire may include:through holes formed at the penetrating portion penetrating between thetop conductive layer and the bottom conductive layer of the board or thepart of layers of the board; and pattern wires formed on the topconductive layer and the bottom conductive layer of the penetratingportion.

According to a sixth aspect of the invention, when a plurality of thewires are formed in the board, both ends or electrically identicalportions of each wire may be electrically connectable to both ends orelectrically identical positions of another wire.

According to a seventh aspect of the invention, wherein the penetrationhole may have a circular shape, and the wire may be formed in a circularshape along the periphery of the penetration hole.

According to an eighth aspect of the invention, wherein the AC currentmay be an AC current having a frequency of a radio frequency band.

According to a ninth aspect of the invention, there is provided avoltage detection printed board comprising: a board having a penetrationhole that penetrates the board; and a wire that is formed along theperiphery of the penetration hole, wherein, when a conductor, in whichan AC voltage is generated, is disposed to pass through the penetrationhole, the wire functions as an electrode of a capacitor by making a pairwith a portion of the conductor facing the wire.

According to a tenth aspect of the invention, the wire may include:along the periphery of the penetration hole, a plurality of throughholes penetrating the board; and pattern wires formed on a topconductive layer and a bottom conductive layer of the board so as toconnect the through holes.

According to an eleventh aspect of the invention, the wire may include:along the periphery of the penetration hole, a plurality of throughholes penetrating between the top conductive layer and the bottomconductive layer of the board or a part of layers of the board; and apattern wire formed on at least one layer between the top conductivelayer and the bottom conductive layer of the penetrating portion so asto connect the through holes.

According to a twelfth aspect of the invention, the through holes mayhave a circular shape, and the wire may be formed in a circular shapealong the periphery of the penetration hole.

According to a thirteenth aspect of the invention, the AC voltage may bean AC voltage having a frequency of a radio frequency band.

According to a fourteenth aspect of the invention, there is provided acurrent/voltage detector that detects an AC current flowing in a powertransmission conductor to be used as an AC power transmission path andan AC voltage generated in the power transmission conductor, thecurrent/voltage detector comprising: a current detection printed boardhaving a first penetration hole that penetrates the board, andincluding: at least one first wire that is formed in a coiled shape andhas both ends by penetrating the board along the periphery of the firstpenetration hole and alternately connecting a front surface layer and arear surface layer of the board; and a second wire for output that isconnected to all or a part of both ends of the first wire, wherein whenthe power transmission conductor, in which an AC current flows, isdisposed to pass through the first penetration hole, a current flowingin the first wire is output through electromagnetic induction; and avoltage detection printed board having a second penetration hole thatpenetrates the board, and including: a third wire that is formed alongthe periphery of the second penetration hole; and a fourth wire foroutput that is connected to a part of the third wire, wherein when thepower transmission conductor, in which an AC voltage is generated, isdisposed to pass through the second penetration hole, the third wiremakes a pair with a portion of the power transmission conductor facingthe third wire and functions as an electrode of a capacitor, and avoltage generated in the third wire is output from the fourth wire.

According to a fifteenth aspect of the invention, the first wire mayinclude: through holes formed at the penetrating portion of the board;and pattern wires formed on the front surface layer and the rear surfacelayer.

According to a sixteenth aspect of the invention, the third wire mayinclude: along the periphery of the second penetration hole, a pluralityof through holes penetrating the board; and pattern wires formed on thefront surface layer and the rear surface layer of the board to connectthe through holes.

According to a seventeenth aspect of the invention, there is provided acurrent/voltage detector that detects an AC current flowing in a powertransmission conductor to be used as an AC power transmission path andan AC voltage generated in the power transmission conductor, thecurrent/voltage detector comprising: a current detection printed boardhaving a first penetration hole that penetrates the board, andincluding: at least one first wire that is formed in a coiled shape andhas both ends by penetrating between a top conductive layer and a bottomconductive layer of the board along the periphery of the firstpenetration hole and alternately connecting the top conductive layer andthe bottom conductive layer of the board, and/or at least one wire thatis formed in a coiled shape and has both ends by penetrating a part oflayers of the board and alternately connecting a top conductive layerand a bottom conductive layer of the penetrating portion, and a secondwire for output that is connected to all or a part of both ends of thefirst wire, wherein when the power transmission conductor, in which anAC current flows, is disposed to pass through the first penetrationhole, a current flowing in the first wire is output throughelectromagnetic induction; and a voltage detection printed board havinga second penetration hole that penetrates the board, and including: athird wire that is formed along the periphery of the second penetrationhole; and a fourth wire for output that is connected to a part of thethird wire, wherein when the power transmission conductor, in which anAC voltage is generated, is disposed to pass through the secondpenetration hole, the third wire makes a pair with a portion of thepower transmission conductor facing the third wire and functions as anelectrode of a capacitor, and a voltage generated in the third wire isoutput from the fourth wire.

According to an eighteenth aspect of the invention, the first wire mayinclude: through holes formed at the penetrating portion penetratingbetween the top conductive layer and the bottom conductive layer of theboard or the part of layers of the board; and pattern wires formed onthe top conductive layer and the bottom conductive layer of thepenetrating portion.

According to a nineteenth aspect of the invention, the third wire mayinclude: along the periphery of the penetration hole, a plurality ofthrough holes penetrating between the top conductive layer and thebottom conductive layer of the board or a part of layers of the board;and a pattern wire formed on at least one layer between the topconductive layer and the bottom conductive layer of the penetratingportion so as to connect the through holes.

According to a twentieth aspect of the invention, when a plurality ofthe first wires are formed in the board, both ends or electricallyidentical portions of each wire may be electrically connectable to bothends or electrically identical positions of another wire.

According to a twenty-first aspect of the invention, the firstpenetration hole provided in the current detection printed board and thesecond penetration hole provided in the voltage detection printed boardmay be substantially coaxially located.

According to a twenty-second aspect of the invention, thecurrent/voltage detector may further comprise: a first conversioncircuit that converts the current output from the second wire of thecurrent detection printed board into a predetermined voltage level; afifth wire that outputs the voltage converted by the first conversioncircuit; a second conversion circuit that converts the voltage outputfrom the fourth wire of the voltage detection printed board into apredetermined voltage level; and a sixth wire that outputs the voltageconverted by the second conversion circuit.

According to a twenty-third aspect of the invention, the firstconversion circuit may be provided on the current detection printedboard, and the second conversion circuit may be provided on the voltagedetection printed board.

According to a twenty-fourth aspect of the invention, thecurrent/voltage detector may further comprises: a conductor casing thatfixes the current detection printed board and the voltage detectionprinted board therein, wherein the casing may have: on an axis passingthrough the first penetration hole provided in the current detectionprinted board and the second penetration hole provided in the voltagedetection printed board, a penetration hole through which the powertransmission conductor passes; an opening through which a magnetic fluxacting on the first wire passes; an opening that allows the third wireand the power transmission conductor to be not shielded; an openingthrough which the fifth wire is led to the outside; and an openingthrough which the sixth wire is led to the outside, and wherein thecasing may be configured to cover the current detection printed boardand the voltage detection printed board, excluding the openings.

According to a twenty-fifth aspect of the invention, the casing mayinclude: a first casing that fixes the current detection printed board;a second casing that fixes the voltage detection printed board; a firstcover that covers the first casing; and a second cover that covers thesecond casing, and the first casing and the second casing are disposedsuch that both sides thereof overlap each other.

According to a twenty-sixth aspect of the invention, a shield memberthat reduces the amount of an electromagnetic wave entering from a sideof the first wire into a side of the first conversion circuit may beprovided in at least one of the first casing and the first cover.

According to a twenty-seventh aspect of the invention, a shield memberthat reduces the amount of an electromagnetic wave entering from a sideof the third wire into a side of the second conversion circuit may beprovided in at least one of the second casing and the second cover.

According to a twenty-eighth aspect of the invention, the first casingand the second casing may be formed in a single body.

According to a twenty-ninth aspect of the invention, the casing mayinclude a fixing unit that substantially fixes the relative positionbetween the power transmission conductor, and the current detectionprinted board and the voltage detection printed board.

According to a thirtieth aspect of the invention, the AC power may be ACpower having a frequency of a radio frequency band.

According to a thirty-first aspect of the invention, there is provided acurrent detector that detects an AC current flowing in a powertransmission conductor to be used as an AC power transmission path, thecurrent detector comprising: a current detection printed board having afirst penetration hole that penetrates the board, and including: atleast one first wire that is formed in a coiled shape and has both endsby penetrating the board along the periphery of the first penetrationhole and alternately connecting a front surface layer and a rear surfacelayer of the board, and a second wire for output that is connected toall or a part of both ends of the first wire, wherein when the powertransmission conductor, in which an AC current flows, is disposed topass through the first penetration hole, a current flowing in the firstwire is output through electromagnetic induction.

According to a thirty-second aspect of the invention, there is provideda current detector that detects an AC current flowing in a powertransmission conductor to be used as an AC power transmission path, thecurrent detector comprising: a current detection printed board having afirst penetration hole that penetrates the board, and including: atleast one first wire that is formed in a coiled shape and has both endsby penetrating between a top conductive layer and a bottom conductivelayer of the board along the periphery of the penetration hole andalternately connecting the top conductive layer and the bottomconductive layer of the board, and/or at least one first wire that isformed in a coiled shape and has both ends by penetrating a part oflayers of the board and alternately connecting a top conductive layerand a bottom conductive layer of the penetrating portion; and a secondwire for output that is connected to all or a part of both ends of thefirst wire, wherein when the power transmission conductor, in which anAC current flows, is disposed to pass through the first penetrationhole, and a current flowing in the first wire is output throughelectromagnetic induction.

According to a thirty-third aspect of the invention, the currentdetector may further comprise: a first conversion circuit that convertsthe current output from the second wire of the current detection printedboard into a predetermined voltage level; and a third wire that outputsthe voltage converted by the first conversion circuit.

According to a thirty-fourth aspect of the invention, the firstconversion circuit may be provided on the current detection printedboard.

According to a thirty-fifth aspect of the invention, the currentdetector may further comprise: a conductor casing that fixes the currentdetection printed board therein, wherein the casing has: on an axispassing through the first penetration hole provided in the currentdetection printed board; a penetration hole through which the powertransmission conductor passes; an opening through which a magnetic fluxacting on the first wire passes; and an opening through which a thirdwire is led to the outside, and wherein the casing is configured tocover the current detection printed board, excluding the openings.

According to a thirty-sixth aspect of the invention, the casing mayinclude: a first casing that fixes the current detection printed board;and a first cover that covers the first casing.

According to a thirty-seventh aspect of the invention, a shield memberthat reduces the amount of an electromagnetic wave entering from thefirst wire into the first conversion circuit may be provided in at leastone of the first casing and the first cover.

According to a thirty-eighth aspect of the invention, the casing mayinclude a fixing unit that substantially fixes the relative positionbetween the power transmission conductor and the current detectionprinted board.

According to a thirty-ninth aspect of the invention, the AC power may beAC power having a frequency of a radio frequency band.

According to a fortieth aspect of the invention, there is provided avoltage detector that detects an AC voltage generated in a powertransmission conductor to be used as an AC power transmission path, thevoltage detector comprising: a voltage detection printed board having afirst penetration hole that penetrates the board, and including a firstwire that is formed along the periphery of the first penetration hole,and a second wire for output that is connected to a part of the firstwire, wherein when the power transmission conductor, in which an ACvoltage is generated, is disposed to pass through the first penetrationhole, the first wire functions as an electrode of a capacitor by makinga pair with a portion of the power transmission conductor facing thefirst wire, and a voltage generated in the first wire is output from thesecond wire.

According to a forty-first aspect of the invention, the voltage detectormay further comprise a first conversion circuit that converts thevoltage output from the second wire of the voltage detection printedboard into a predetermined voltage level; and a third wire that outputthe voltage converted by the first conversion circuit.

According to a forty-second aspect of the invention, the firstconversion circuit may be provided on the voltage detection printedboard.

According to a forty-third aspect of the invention, the voltage detectormay further comprise a conductor casing that fixes the voltage detectionprinted board therein, wherein the casing may have: on an axis passingthrough the first penetration hole provided in the voltage detectionprinted board; a penetration hole through which the power transmissionconductor passes; an opening that allows the first wire and the powertransmission conductor to be not shielded, and an opening through whichthe third wire is led to the outside; and the casing may be configuredto cover the voltage detection printed board, excluding the openings.

According to a forty-fourth aspect of the invention, the casing mayinclude: a first casing that fixes the voltage detection printed board;and a first cover that covers the second casing.

According to a forty-fifth aspect of the invention, a shield member thatreduces the amount of an electromagnetic wave entering from a side ofthe first wire into a side of the first conversion circuit may beprovided in at least one of the first casing and the first cover.

According to a forty-sixth aspect of the invention, the casing mayinclude a fixing unit that substantially fixes the relative positionbetween the power transmission conductor and the voltage detectionprinted board.

According to a forty-seventh aspect of the invention, wherein the ACpower may be AC power having a frequency of a radio frequency band.

According to the first and fourth aspects of the invention, since thecoiled wire is formed in the printed board, the printed board can have afunction of a current transformer.

According to the second and fifth aspects of the invention, since thethrough holes and pattern wires form the coiled wire, unlike the relatedart, there is no case where a self-resonant frequency or a degree ofcoupling of the current transformer changes due to a variation inwinding internal or winding strength. For this reason, when a pluralityof current detection printed boards are formed, a variation in currentdetection value of the individual current detection printed boards canbe reduced.

According to the seventh aspect of the invention, when the conductor, inwhich the AC current flows, is disposed to pass through the penetrationhole, a cylindrical (a circular shape in section) conductor ispreferably used as the conductor. Further, since a magnetic flux isgenerated around the conductor, the magnetic flux can efficiently passthrough the wire having the coiled shape.

Like the eighth aspect of the invention, in case of an AC current havinga frequency of a radio frequency band, a variation in winding intervalor winding strength may have a large effect on the current detectionvalue. However, according to the current detection printed board havingthe configuration of the invention, even though an AC current having afrequency of a radio frequency band is adopted, an influence thereof canbe suppressed to the minimum.

According to the ninth aspect of the invention, the wire that is formedalong the penetration hole provided in the board functions as anelectrode of the capacitor. Therefore, the printed board can have avoltage detection function.

According to the tenth and eleventh aspects of the invention, with thethrough holes and the pattern wires, a ring-shaped wire that functionsas an electrode of the capacitor can be formed in the printed board.Therefore, when a plurality of voltage detection printed boards areformed, a variation in voltage detection value of the individual voltagedetection printed boards can be reduced.

Further, the wire has a feature in that the through holes are utilized,as well as the pattern wires. That is, only with the pattern wires, thering-shaped wire does not have a thickness enough to functioning as anelectrode of the capacitor. For this reason, with the through holes, thethickness of the ring-shaped wire can be made large.

According to the twelfth aspect of the invention, when the conductor, inwhich the AC voltage is generated, is disposed to pass through thepenetration hole, a cylindrical (a circular shape in section) conductoris preferably used as the conductor. Further, in case of the circularshape, an inter-electrode distance of the capacitor is likely to be keptconstant, and a variation in detection value can be reduced.

Like the thirteenth aspect of the invention, in case of an AC voltagehaving a frequency of a radio frequency band, a structural variation mayhave a large effect on the voltage detection value. However, accordingto the voltage detection printed board having the configuration of theinvention, even though an AC voltage having a frequency of a radiofrequency band is adopted, an influence thereof can be suppressed to theminimum.

According to the fourteenth and seventeenth aspects of the invention,current detection can be performed by the current detection printedboard, and voltage detection can be performed by the voltage detectionprinted board. Further, according to the thirty-first and thirty-secondaspects of the invention, current detection can be performed by thecurrent detection printed board. In addition, according to the fortiethaspect of the invention, voltage detection can be performed by thevoltage detection printed board.

According to the twenty-first aspect of the invention, at least portionsof the power transmission conductor penetrating the current/voltagedetector can be formed in a linear shape (for example, a cylindricalshape). That is, since it is necessary to form the power transmissionconductor in a complex shape, manufacturing of the power transmissionconductor can be simplified.

According to the twenty-third aspect of the invention, the second wireand the fourth wire can be formed by pattern wires (as occasion demands,including through holes). Accordingly, a variation in detection valuedue to a variation in shape of the wire or the like can be reduced.Further, the number of assembling steps can be reduced.

Further, the effects of the thirty-fourth aspect of the invention arethe same as the effects about the second wire. In addition, the effectsof the forty-second aspect of the invention are the same as the effectsabout the fourth wire.

According to the twenty-fourth aspect of the invention, the printedboards are shielded, excluding the openings required for the currentdetection printed board and openings required for the voltage detectionprinted board. Therefore, an influence of an electromagnetic wave on theprinted boards can be reduced as small as possible.

Further, the effects of the thirty-fifth aspect of the invention are thesame as the effects about the current detection printed board. Inaddition, the effects of the forty-third aspect of the invention are thesame as the effects about the voltage detection printed board.

According to the twenty-sixth aspect of the invention, an influence ofan electromagnetic wave on the first conversion circuit can be reducedas small as possible. Further, the effects of the thirty-seventh aspectof the invention are the same as the above-described effects.

According to the twenty-seventh aspect of the invention, an influence ofan electromagnetic wave on the second conversion circuit can be reducedas small as possible. Further, the effects of the forty-fifth aspect ofthe invention are the same as the above-described effects.

According to the twenty-eighth aspect of the invention, for example, thefirst casing and the second casing are formed in a signal body such thatthe first penetration hole provided in the current detection printedboard and the second penetration hole provided in the voltage detectionprinted board are substantially coaxially located. Therefore, the numberof steps of substantially coaxially locating the first penetration holeand the second penetration hole can be removed.

According to the twenty-ninth aspect of the invention, the relativeposition between the power transmission conductor, and the currentdetection printed board and the voltage detection printed board can bekept substantially constant. Further, according to the thirty-eighthaspect of the invention, the relative position between the powertransmission conductor and the current detection printed board can bekept substantially constant. In addition, according to the forty-sixthaspect of the invention, the relative position between the powertransmission conductor and the voltage detection printed board can bekept substantially constant.

Like the thirtieth aspect of the invention, in case of an AC powerhaving a frequency of a radio frequency band, a variation in windinginterval or winding strength has a large effect on the current detectionvalue. Further, a structural variation has a large effect on the voltagedetection value. However, according to the current/voltage detectorhaving the configuration of the invention, even though an AC powerhaving a frequency of a radio frequency band is adopted, an influencethereof can be suppressed to the minimum.

Further, the effects of the thirty-ninth aspect of the invention are thesame as the effects about current detection. In addition, the effects ofthe forty-seventh aspect of the invention are the same as the effectsabout voltage detection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1D are diagrams showing an example of a current detectionprinted board 1 according to the invention.

FIG. 2 is a diagram showing a case where a power transmission conductor66, in which an AC current flows, and an insulator 69 covering the powertransmission conductor 66 are disposed to pass through a penetrationhole 101 provided in the current detection printed board 1.

FIGS. 3A to 3E are diagrams showing another example of the currentdetection printed board 1 according to the invention.

FIGS. 4A and 4B are diagram showing another example of a coiled wire 10.

FIG. 5 is diagram showing another example of the current detectionprinted board 1 according to the invention.

FIG. 6 is a connection diagram of the current detection printed board 1shown in FIG. 5.

FIG. 7 is a diagram showing another example of the current detectionprinted board 1 according to the invention.

FIGS. 8A to 8E are diagrams showing the arrangement examples of thefirst coiled wire 10-1 and the second coiled wire 10-2.

FIGS. 9A to 9D are diagrams showing an example of a voltage detectionprinted board 2 according to the invention.

FIGS. 10A to 10E are diagrams showing another example of the voltagedetection printed board 2 according to the invention.

FIGS. 11A and 11B show another example of a ring-shaped wire 30.

FIGS. 12A to 12C are schematic exterior views of a current/voltagedetector 3 according to a third embodiment of the invention.

FIGS. 13A and 13B are diagrams showing the schematic configuration ofthe current/voltage detector 3 shown in FIGS. 12A to 12C.

FIGS. 14A to 14C are diagrams of a casing main body 300.

FIGS. 15A and 15B are diagrams three-dimensionally showing the casingmain body 30.

FIGS. 16A and 6B are diagrams when the current detection printed board 1and the voltage detection printed board 2 are mounted on the casing mainbody 300 in a state where a current detector cover 301 and a voltagedetector cover 302 are not mounted.

FIG. 17 is a cross-sectional view showing a case where the powertransmission conductor 66 and the insulator 69 covering the powertransmission conductor 66 penetrate the current/voltage detector 3.

FIGS. 18A and 18B show an example of an application of a second shieldportion 314.

FIGS. 19A and 19B show a modification of the current detection printedboard 1, the voltage detection printed board 2, and the casing.

FIG. 20 is a diagram showing an example where the current detectionprinted board 1 and the voltage detection printed board 2 areaccommodated in separate casings, thereby forming the current detector310 and the voltage detector 320 separately.

FIG. 21 is a diagram showing an application when the current detector310 and the voltage detector 320 are provided separately.

FIG. 22 is a diagram showing a case where the voltage detector 320 isdisposed near the input and the current detector 310 is disposed at theback of the voltage detector 320.

FIG. 23 is a diagram showing a fixing method of the insulator 69.

FIG. 24 is a diagram showing a fixing method of the insulator 69 whenonly the current detector 310 is used separately.

FIG. 25 is a diagram showing a case where the sizes of the powertransmission conductor 66 and the insulator 69 are suited to the size ofthe current/voltage detector 3 in the current/voltage detector 3 shownin FIG. 23.

FIG. 26 is a block diagram of an example of a high-frequency powersupply system that uses an impedance matching device.

FIG. 27 is a schematic circuit diagram of a current detector 80 and avoltage detector 90 provided between an input terminal and a matchingcircuit 67 of an impedance matching device 63.

FIG. 28 is a schematic exterior view of the current detector 80 and thevoltage detector 90.

FIGS. 29A to 29C are explanatory views illustrating the configuration ofthe current detector 80 and the voltage detector 90 shown in FIG. 28.

FIG. 30 is a circuit diagram showing a case where the current detector80 and the voltage detector 90 are provided between the matching circuitand the output terminal in the impedance matching device.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the details of the invention will be described withreference to the drawings.

(1) Current Detection Printed Board

FIGS. 1A to 1D are diagrams showing an example of a current detectionprinted board 1 according to the invention.

Specifically, FIG. 1A is a plan view of the current detection printedboard 1 (as viewed from the above). FIG. 1B is a schematic view of aportion (a portion A surrounded by a dotted line) of FIG. 1A onmagnified scale. FIG. 1C is a diagram showing linear expansion forsimplification of FIG. 1B. FIG. 1D shows a wire of the current detectionprinted board 1 when FIG. 1C is viewed from the side. Moreover, asregards the wire shown in FIG. 1D, portions that are not typicallyviewed are shown in perspective view for explanation.

As shown in FIGS. 1A to 1D, the current detection printed board 1 isprovided with a penetration hole 101 that penetrates a board. A wire 10(hereinafter, referred to as a coiled wire 10) that is formed in acoiled shape is provided along the periphery of the penetration hole101. The coiled wire 10 is formed in a coiled shape having both ends byalternately connecting a front surface 121 and a rear surface 122 of theboard while penetrating the board. Portions of the wire penetrating theboard are formed by through holes 11 and wires of the front surface andthe rear surface of the board are formed by pattern wires 12 and 13.

Moreover, in FIGS. 1B and 1C, portions indicated by dotted linesrepresent pattern wires of the rear surface of the board. These portionsare in perspective view, and thus indicated by dotted lines. Outputwires 21 and 22 are connected to both ends 10 a and 10 b of the coiledwire 10. The output wires are connected to output terminals 23 and 24.

In this example, the board having a double-sided structure (hereinafter,referred to a double-sided board) is used. Accordingly, the patternwires are formed on a front surface layer and a rear surface layer ofone insulator member 110.

The coiled wire 10 is an example of a coiled first wire of theinvention, and the output wires 21 and 22 are examples of the secondwire of the invention.

FIG. 2 is a diagram showing a case where a power transmission conductor66, in which an AC current flows, and an insulator 69 covering the powertransmission conductor 66 are disposed to pass through the penetrationhole 101 provided in the current detection printed board 1. Moreover,for simplification, the wire is not shown. Further, in this embodimentand the following embodiments, a case where the current detectionprinted board or a voltage detection printed board described below isprovided between an input terminal and a matching circuit 67 of animpedance matching device 63.

In case of the current detection printed board 1 shown in FIG. 1, asshown in FIG. 2, when the power transmission conductor 66, in which anAC current flows, is disposed to pass through the penetration hole 101,a current flows in the coiled wire 10 by electromagnetic induction. Thatis, the printed board can have a current transformer. Specifically, acurrent transformer can be formed in the current detection printed board1.

Accordingly, the portions of the coiled wire 10 correspond to thecurrent transformer 81 in the circuit diagram shown in FIG. 27.

With this configuration, the portions of the coiled wire 10 are formedby the through holes and the pattern wires, and thus there is almost novariation in shape or position. Accordingly, there is almost novariation in winding interval or winding strength. Therefore, when aplurality of current detection printed boards 1 are formed, a variationin current detection value of the individual current detection printedboards 1 can be reduced.

As described below, a current conversion circuit 51 corresponding to thecurrent conversion circuit 84 shown in FIG. 27 may be provided on thecurrent detection printed board 1 of FIG. 1. In this case, the outputterminals 23 and 24 shown in FIG. 1 are not required, and the outputwires 21 and 22 of the coiled wire 10 are directly connected to thecurrent conversion circuit 51.

The insulator member 110 of the board is formed of, for example, glassepoxy. Relative magnetic permeability of the insulator member 110 of theboard is smaller than a magnetic material. For this reason, aself-resonant frequency may be higher, compared with a case where acurrent transformer is formed by winding a wire around a magneticmaterial uses as a core, like the related art. Accordingly, an upperlimit of a detectable frequency band is higher than the related art.

FIGS. 3A to 3E are diagrams showing another example of the currentdetection printed board 1 according to the invention.

Specifically, FIG. 3A is a plan view of the current detection printedboard 1. FIG. 3B is a schematic view of a portion (a portion Bsurrounded by a dotted line) of FIG. 3A on magnified scale. FIG. 3C is adiagram showing linear expansion for simplification of FIG. 3B. FIG. 3Dshows a wire of the current detection printed board 1 when FIG. 3C isviewed from the side. FIG. 3E shows the wire of the current detectionprinted board 1 paying emphasis on the output wire 21 as viewed from theside. Moreover, as regards the wire shown in FIGS. 3A to 3E, portionsthat are not typically viewed are shown in perspective view forexplanation. In addition, for convenience, the current detection printedboard 1, through holes 11, pattern wires 12 and 13, and the like arerepresented by the same reference numerals as those in FIGS. 1A to 1D.

The current detection printed board 1 shown in FIGS. 3A to 3E isspecifically the same as the current detection printed board 1 shown inFIGS. 1A to 1D, except that the board has a multilayer structure, andthe coiled wire 10 is formed between inner layers.

Moreover, in this specification, insulator materials constituting theboard having a multilayer structure (hereinafter, referred to as amultilayer board) are appropriately called a first insulator material, asecond insulator material, a third insulator material, . . . in sequencefrom the upper portion of the drawings. Further, conductive layers to beformed between the individual insulator materials of the board areappropriately called a first conductive layer, a second conductivelayer, a third conductive layer, . . . . Further, a conductive layer tobe formed at the front surface of the board is called a front surfacelayer, and a conductive layer to be formed at the rear surface of theboard is called a rear surface layer.

Moreover, although the double-sided board has the front surface layerand the rear surface layer and may be called a multilayer board, sinceonly one insulator material exists, there are no conductive layers to beformed between the individual insulator materials of the board.

In the example of FIGS. 3A to 3E, the insulator materials of the boardinclude three insulator materials of a first insulator material 111, asecond insulator 112, and a third insulator material 113. Then, a firstconductive layer 131 is formed between the first insulator material 111and the second insulator material 112, and a second conductive layer 132is formed between the second insulator material 112 and the thirdinsulator material 113. Further, a front surface layer can be formed ona front surface 121 (a surface on the first insulator material) of theboard. In addition, a rear surface layer can be formed on a rear surface122 (a lower surface of the third insulator material). In the example ofFIGS. 3A to 3E, the rear surface layer of the board is not provided.

For this reason, in FIGS. 3A to 3E, the coiled wire 10 is formed betweenthe first conductive layer 131 and the second conductive layer 132.Accordingly, the coiled wire 10 can have a structure that cannot beviewed from the outside of the board. In this case, portions of thecoiled wire 10 correspond to the current transformer 81 of the circuitdiagram shown in FIG. 27.

Further, as shown in FIG. 3E, the output wire 21 of the coiled wire 10is formed by a pattern wire 21 a connected to one end 10 a of the coiledwire 10 formed in the first conductive layer 131, a through hole 21 b,and a pattern wire 21C formed on the front surface of the board. Theoutput wire 21 is connected to the output terminal 23. The output wire22 of the coiled wire 10 is the same as the output wire 21, and thus thedescription thereof will be omitted.

Moreover, as described below, the current conversion circuit 51corresponding to the current conversion circuit 84 shown in FIG. 27 maybe formed on thee current detection printed board 1 of FIGS. 3A to 3E.In this case, the output terminals 23 and 24 shown in FIGS. 3A to 3E arenot required, and thus the output wires 21 and 22 of the coiled wire 10are directly connected to thee current conversion circuit 51.

FIGS. 4A and 4B are diagram showing another example of the coiled wire10. For example, as shown in FIG. 4A, the coiled wire 10 may be formedbetween the front surface layer of the board and the second conductivelayer 132. Moreover, in FIG. 4A, since the rear surface layer is notprovided on the rear surface 122 of the board, the coiled wire 10 isformed by alternately connecting the front surface layer as a topconductive layer of the board and the second conductive layer 132 as abottom conductive layer of the board.

Further, as shown in FIG. 4B, the coiled wire 10 may be formed betweenthe front surface layer as a top conductive layer and the rear surfacelayer as a bottom conductive layer of the board. Moreover, in FIG. 4B,like FIGS. 1A to 1D, the coiled wire 10 is formed by alternatelyconnecting the front surface layer and the rear surface layer of theboard.

In general, a through hole is one for connection between layers byforming a penetration hole between the layers of the board and providinga conductive layer (for example, copper) in the penetration hole.Moreover, the term ‘between the layers’ may mean ‘between all layers’ or‘between some layers’.

The through hole is a type of inserting a lead line. However, thethrough hole only for connection between the layers is particularlycalled a via hole. Then, the via hole includes a penetration via holethat forms a penetration hole from the front surface of the board to therear surface thereof, and an interstitial via hole that forms apenetration hole only between specific layers. Further, the interstitialvia hole includes a blind via in which a hole is viewed from one surfaceof the board, as shown in FIG. 4A, and a buried via in which a hole isnot viewed from both surfaces of the board, as shown in FIGS. 3A to 3E.

The example shown in FIGS. 3A to 3E and 4 uses a so-called four-layeredboard (four conductive layers including the front surface layer and therear surface layer), but is not intended to limit the invention. Forexample, a multilayer board, such as a three-layered board, asix-layered board, or an eight-layered board, may be used.

FIG. 5 is diagram showing another example of the current detectionprinted board 1 according to the invention. The current detectionprinted board 1 shown in FIG. 5 is different from that of FIG. 1 in thattwo coiled wires 10-1 and 10-2 are provided in the current detectionprinted board 1. Specifically, a first coiled wire 10-1 that is disposednear the outside of the current detection printed board 1 and a secondcoiled wire 10-2 that is disposed closer to the penetration hole 101than the first coiled wire 10-1 does are provided in the currentdetection printed board 1. Further, the first coiled wire 10-1 and thesecond coiled wire 10-2 are formed by through holes and pattern wires,like FIGS. 1B and 1C. For this reason, the descriptions thereof will beomitted. Of course, the multilayer board shown in FIGS. 3A to 3E may beused. Here, the description thereof will be omitted.

As described above, in the current detection printed board 1 shown inFIG. 5, since the two coiled wires 10-1 and 10-2 are provided, variouskinds of current transformers can be formed in one current detectionprinted board 1. This example will be described with reference to FIG.6.

FIG. 6 is a connection diagram of the current detection printed board 1shown in FIG. 5.

As shown in FIG. 5, output terminals 23-1 and 24-1 are connected to bothends 10-1 a and 10-1 b of the first coiled wire 10-1. Further, outputterminals 23-2 and 24-2 are connected to both ends 10-2 a and 10-2 b ofthe second coiled wire 10-2. In this case, with the connection shown inFIG. 6, various kinds of current transformers can be formed in onecurrent detection printed board 1. Moreover, in FIG. 6, ‘x’ meansnon-connection to other terminals.

Specifically, in case of connection (a) in FIG. 6, a current transformerusing the first coiled wire 10-1 is formed in the current detectionprinted board 1.

In case of connection (b) in FIG. 6, a current transformer using thesecond coiled wire 10-2 is formed in the current detection printed board1.

In case of connection (c) in FIG. 6, if the output terminal 23-2 and theoutput terminal 24-1 are connected to each other, a current transformerwhen the first coiled wire 10-1 and the second coiled wire 10-2 areconnected in series to each other is formed. Therefore, in this case, acurrent transformer having larger inductance can be formed, comparedwith the cases (a) and (b) in FIG. 6.

In addition, like connection (d) in FIG. 6, if the output terminal 23-1and the output terminal 23-2 are connected to each other, and the outputterminal 24-1 and the output terminal 24-1 are connected to each other,a current transformer when the first coiled wire 10-1 and the secondcoiled wire 10-2 are connected in parallel with each other.

FIG. 7 is a diagram showing another example of the current detectionprinted board 1 according to the invention. In the current detectionprinted board 1, like FIG. 5, the first coiled wire 10-1 and the secondcoiled wire 10-2 are provided in one current detection printed board 1.The current detection printed board 1 of FIG. 7 is different from thatof FIG. 5 in that the first coiled wire 10-1 and the second coiled wire10-2 are disposed to have a double helix structure. Further, in FIG. 7,like FIG. 5, various kinds of current transformers can be formed in onecurrent detection printed board 1. Moreover, in FIGS. 5 and 7, for easediscrimination of the wires, the positions of the output terminals areshifted from each other, but the invention is not limited thereto.Various kinds of position relationship may be adopted.

As shown in FIG. 7, the first coiled wire 10-1 and the second coiledwire 10-2 can be arranged to have a double helix structure.Alternatively, many arrangement examples may be considered, in additionto the example shown in FIG. 7.

FIGS. 8A to 8E are diagrams showing the arrangement examples of thefirst coiled wire 10-1 and the second coiled wire 10-2. FIGS. 8A to 8Eschematically show the sections of the first coiled wire 10-1 and thesecond coiled wire 10-2 and show various arrangement examples. Moreover,the first coiled wire 10-1 and the second coiled wire 10-2 are shiftedfrom each other with respect to a backward direction as viewed from thepaper. Since portions that are not typically viewed are shown inperspective view for explanation, the wires may seem to overlap eachother.

For example, FIG. 8A shows an example where the first coiled wire 10-1and the second coiled wire 10-2 are formed in the same conductive layer.In this case, the pattern wire of the first coiled wire 10-1 is longerthan that of the second coiled wire 10-2. Of course, the pattern wire ofthe second coiled wire 10-2 may be longer than that of the first coiledwire 10-1.

FIG. 8B shows an example where the first coiled wire 10-1 and the secondcoiled wire 10-2 are formed in the same conductive layer, like FIG. 8A.However, the pattern wires of the first coiled wire 10-1 and the secondcoiled wire 10-2 have the same length.

FIG. 8C shows an example where the through hole of the second coiledwire 10-2 is formed further towards the inside than the first coiledwire 10-1, and the pattern wire of the second coiled wire 10-2 is formedin a conductive layer inside the first coiled wire 10-1.

FIG. 8D shows an example where the through hole of the second coiledwire 10-2 is formed further towards the inside than the first coiledwire 10-1, and the pattern wire of the second coiled wire 10-2 is formedin a conductive layer outside the first coiled wire 10-1.

FIG. 8E shows an example where the through hole of the second coiledwire 10-2 is formed further towards the outside than the first coiledwire 10-1, and the pattern wire of the second coiled wire 10-2 is formedin a conductive layer inside the first coiled wire 10-1.

In addition, various modifications can be considered and easilyconsidered from the above examples, and thus the descriptions thereofwill be omitted. Moreover, as shown in FIGS. 8A and 8B, when the patternwires of the first coiled wire 10-1 and the second coiled wire 10-2 areformed in the same conductive layer, a double-sided board can be used.

In FIGS. 8A to 8E, as the current detection printed board 1 is viewed inplan view, the through holes and the pattern wires of the first coiledwire 10-1 and the second coiled wire 10-2 are shifted from each other.With this configuration, various arrangement examples can be made.Alternatively, as shown in FIG. 8C, if the through hole of the secondcoiled wire 10-2 is formed further towards the inside than the throughhole of the first coiled wire 10-1, and the pattern wire of the secondcoiled wire 10-2 is formed further towards the inside than the patternwire of the first coiled wire 10-1, as viewed in plan view, the patternwires of the first coiled wire 10-1 and the second coiled wire 10-2 maybe partially overlap each other. Of course, the relationship between thefirst coiled wire 10-1 and the second coiled wire 10-2 may be reversed.

In FIGS. 5 and 7, an example where the two coiled wires 10 are providedin one current detection printed board 1 has been illustrated, but thenumber of coiled wires is not limited thereto. For example, three ormore coiled wires 10 may be provided in one current detection printedboard 1. Of course, with this configuration, the number of combinationsof the coiled wires 10 to be formed in one current detection printedboard 1 can be increased. Further, as described below, when the currentconversion circuit 51 is provided on the current detection printed board1, the same can be applied. In this case, as described above, the wiresmay be connected near both ends of the coiled wires 10 or may beconnected in the current conversion circuit 51. That is, both ends ofeach wire or positions electrically identical to both ends thereof areelectrically connectable to both ends of another wire or positionselectrically identical to both ends thereof.

Next, the effects of a case where a plurality of coiled wires 10 areprovided in the current detection printed board 1, as shown in FIGS. 5and 7, will be described.

In general, a coil (also referred to as an inductor) has a frequencycharacteristic, and the characteristic changes according to a frequencyto be used. Specifically, a detection level of a current is low in aregion where a frequency is low. For this reason, the coil is used in aregion where a frequency is high. However, an excessively high frequencycauses resonance. A frequency at the time of resonance is referred to asa resonant frequency. Near the resonant frequency, a change in detectionlevel of a current is excessively large, and thus it is unsuitable forcurrent detection. For this reason, schematically, a detectablefrequency band is limited. That is, a usable frequency has an upperlimit and a lower limit.

If inductance of the coil becomes large, the detectable frequency bandgoes toward a lower frequency. Meanwhile, if inductance of the coilbecomes small, the detectable frequency band goes toward a higherfrequency. For this reason, it is necessary to select inductance of thecoiled wire 10 to an appropriate value using a frequency of an ACcurrent flowing in the power transmission conductor 66.

The above-described high-frequency power supply device 61 outputsdifferent frequencies of high-frequency power according to the uses. Forexample, a frequency of 2 MHz, 13.56 MHz, or the like is used accordingto the uses. For this reason, since it is necessary to select inductanceof the coiled wire 10 according to the frequencies. Accordingly, ifvarious kinds of current transformers can be formed in one currentdetection printed board 1, convenience can be increased. For example, ifboth the current transformer for 2 MHz and the current transformer for13.56 MHz can be formed, it is unnecessary to prepare the currentdetection printed boards 1 for the individual frequencies. Therefore,kinds of products can be reduced.

Like the examples shown in FIGS. 1A to 1D and FIGS. 3A to 3E, when thecoiled wire 10 is a simplex wound wire, there is a limit to increase thenumber of turns. Then, there is also a limit to increase inductance.Here, in case of serial connection indicated by (c) of FIG. 6,inductance of the coiled wire 10 can be increased, and thus thedetectable frequency band can be made low.

(2) Voltage Detection Printed Board

FIGS. 9A to 9D are diagrams showing an example of a voltage detectionprinted board 2 according to the invention.

Specifically, FIG. 9A is a plan view of the voltage detection printedboard 2. FIG. 9B is a schematic view of a portion (a portion Csurrounded by a dotted line) of FIG. 9A on magnified scale. FIG. 9C is adiagram showing linear expansion for simplification of FIG. 9B. FIG. 9Dshows a wire of the voltage detection printed board 2 when FIG. 9C isviewed from the side. Moreover, as regards the wire shown in FIG. 9D,portions that are not typically viewed are shown in perspective view forexplanation.

As shown in FIGS. 9A to 9D, the voltage detection printed board 2 has apenetration hole 201 that penetrates a board, and a ring-shaped wire 30that is provided in the vicinity of the penetration hole 201. Thering-shaped wire 30 is formed by, along the periphery of the penetrationhole 201, providing a plurality of through holes 31 that penetrate theboard and patterns wires 32 and 33 that connect the through holes to afront surface 221 and a rear surface 222 of the board. For this reason,the individual through holes are provided between the pattern wires 32and 33 of the front surface of the rear surface of the board. Further,the thickness of each of the through holes is formed to have thesubstantially same thickness as the thickness of the board. In such amanner, the ring-shaped 30 is obtained.

Moreover, in FIGS. 9B and 9C, the pattern wires 32 and 33 of the frontsurface and the rear surface of the board overlap each other. Further,an output wire 40 is connected to the ring-shaped wire 30.

In the voltage detection printed board 2 in FIGS. 9A to 9D, when a powertransmission conductor 66, in which an AC voltage is generated, isdisposed to pass through the penetration hole 201, the ring-shaped wire30 and a portion of the power transmission conductor 66 facing thering-shaped wire 30 function as electrodes of a capacitor. That is, theprinted board can have a function as the electrodes of the capacitor.Accordingly, portions of the ring-shaped wire 30 correspond to theelectrode 91 b of the capacitor of the circuit diagram in FIG. 27.

With this configuration, the portions of the ring-shaped wire 30 areformed by the through holes 31 or the pattern wires 32 and 33.Accordingly, there is almost no variation in shape or position.Therefore, when a plurality of voltage detection printed boards 2 areformed, a variation in voltage detection value of the individual voltagedetection printed boards 2 can be reduced.

Moreover, as described below, a voltage conversion circuit 53corresponding to the voltage conversion circuit shown in FIG. 27 may beprovided on the voltage detection printed board 2 of FIGS. 9A to 9D. Inthis case, an output terminal 41 shown in FIGS. 9A to 9D is notrequired, and thus the output wire 40 of the ring-shaped wire 30 isdirectly connected to the voltage conversion circuit 53.

Moreover, the ring-shaped wire 30 is an example of a third wire of theinvention (a first wire in the case of a voltage detector), and theoutput wire 40 is an example of a fourth wire of the invention (a secondwire in the case of a voltage detector).

FIGS. 10A to 10E are diagrams showing another example of the voltagedetection printed board 2 according to the invention.

Specifically, FIG. 10A is a plan view of the voltage detection printedboard 2. FIG. 10B is a schematic view of a portion (a portion Dsurrounded by a dotted line) of FIG. 10A on magnified scale. FIG. 100 isa diagram showing linear expansion for simplification of FIG. 10B. FIG.10D shows a wire of the voltage detection printed board 2 when FIG. 100is viewed from the side. FIG. 10E shows the wire of the voltagedetection printed board 2 paying emphasis on the output wire 40 asviewed from the side. Moreover, as regards the wire shown in FIGS. 10Ato 10E, portions that are not typically viewed are shown in perspectiveview for explanation. In addition, for convenience, the voltagedetection printed board 2, through holes 31, pattern wires 32 and 33,and the like are represented by the same reference numerals as those inFIGS. 9A to 9D.

The voltage detection printed board 2 shown in FIGS. 10A to 10E isspecifically the same as the voltage detection printed board 2 shown inFIGS. 9A to 9D, except that the board has a multilayer structure, andthe ring-shaped wire 30 is formed between inner layers. This is the sameas FIGS. 3A to 3E, and the description thereof will be omitted.

For this reason, in FIGS. 10A to 10E, the ring-shaped wire 30 is formedbetween a first conductive layer 231 and a second conductive layer 232.Accordingly, the ring-shaped wire 30 may not be viewed. Further, in thiscase, the portions of the ring-shaped wire 30 correspond to theelectrode 91 b of the capacitor of the circuit diagram in FIG. 27.

The ring-shaped wire 30 is formed by pattern wires 40 a connected to oneend 30 a of the ring-shaped wire 30 formed in the first conductive layer231, through holes 40 b, and pattern wires 40 c formed on the frontsurface of the board 40 c, as shown in FIG. 10E. The output wire 40 isconnected to an output terminal 41.

Moreover, unlike the above description, as shown in FIGS. 11A and 11B,the ring-shaped wire 30 may be formed.

FIGS. 11A and 11B show another example of the ring-shaped wire 30.

FIG. 11A shows an example where an additional pattern wire forconnecting the through holes is provided between a top conductive layerand a bottom conductive layer at penetration portions of the throughholes 31. In this example, four pattern wires of a pattern wire 34, apattern wire 35, a pattern wire 36, and a pattern wire 37 are providedin sequence from the upper portion of the board. As such, three or morepattern wires may be provided.

FIG. 11B shows an example where a pattern wire 38 is provided in onlyone layer between the top conductive layer and the bottom conductivelayer at the penetration portions of the through holes 31. As such, onlyone pattern wire may be provided.

Accordingly, a pattern wire may be provided in at least one layerbetween the top conductive layer and the bottom conductive layer at thepenetration portions of the through holes so as to connect the throughholes. In this case, the portions of the ring-shaped wire 30 correspondto the electrode 91 b of the capacitor of the circuit diagram in FIG.27.

(3) Current/Voltage Detector

FIGS. 12A to 12C are schematic exterior views of a current/voltagedetector 3 according to a third embodiment of the invention.Specifically, FIG. 12A is a schematic exterior view three-dimensionallyshowing the current/voltage detector 3. FIG. 12B is a schematic exteriorview of a conductor casing as viewed from the side. FIG. 12C is adiagram when the conductor casing of FIG. 12B is removed.

As shown in FIG. 12A, like the related art, the current/voltage detector3 has a structure in which a power transmission conductor 66 canpenetrate a casing. Moreover, the power transmission conductor 66 and aninsulator 69 surrounding the power transmission conductor 66 are notincluded in the current/voltage detector 3 but are just shown forexplanation. Further, the insulator 69 insulates the power transmissionconductor 66 and the current/voltage detector 3. For this reason, anactual length of the insulator 69 is shorter than the length of theinsulator 69 shown in the drawing, but it is shown like FIG. 12A forsimplification of the drawing. The same is applied to other drawings(for example, FIG. 17).

As shown in FIG. 12C, the current detection printed board 1 and thevoltage detection printed board 2 are accommodated in the casing. Forthis reason, a current that flows in the power transmission conductor 66passing through the casing can be detected by the current detectionprinted board 1, and a voltage that is generated in the powertransmission conductor 66 can be detected by the voltage detectionprinted board 2.

That is, in the example shown in FIG. 12B, a left portion of thecurrent/voltage detector 3 corresponds to a current detector 310 and aright portion thereof corresponds to a voltage detector 320. Moreover,the casing is formed of a conductor, such as aluminum or the like. Then,the current detector 310 corresponds to the current detector 80 shown inFIG. 27, and the voltage detector 320 corresponds to the voltagedetector 90 shown in FIG. 27.

FIGS. 13A and 13B are diagrams showing the schematic configuration ofthe current/voltage detector 3 shown in FIGS. 12A to 12C. Specifically,FIG. 13A is a diagram showing the configuration of the current/voltagedetector 3. FIG. 13B is a schematic view showing when individual partsof FIG. 13A are assembled. Moreover, in FIGS. 13A and 13B, the shapes ofthe individual parts are schematic. For example, a penetration holethrough which the power transmission conductor 66 passes or an openingthrough which a magnetic flux passes is provided in the casing or theboard, but it is not shown in the drawings. Further, in FIGS. 13A and13B, portions that are not viewed from the outside are schematicallyindicated by dotted lines.

As shown in FIG. 13A, the current/voltage detector 3 has a casing mainbody 300, and the current detection printed board 1, the voltagedetection printed board 2, a current detector cover 301, and a voltagedetector cover 302 that are fixed to the casing main body 300. Ofcourse, parts, such as screws or beads, for fixing the above-describedconstituents, but they are regarded as portions of the constituents andare not shown for simplification of explanation. Further, as indicatedby an arrow in FIG. 13A, if the constituents are fixed to the casingmain body 300, as shown in FIG. 13B, the current detection printed board1 and the voltage detection printed board 2 are fixed in the casing mainbody 300, and the current detection printed board 1 and the voltagedetection printed board 2 are covered with the covers 301 and 302,respectively.

Moreover, in the casing main body 300, a portion where the currentdetection printed board 1 is fixed is an example of a first casing ofthe invention, and a portion where the voltage detection printed board 2is fixed is an example of a second casing of the invention (a firstcover in the case of a voltage detector). Further, the current detectorcover 301 is an example of a first cover of the invention, and thevoltage detector cover 302 is an example of a second cover of theinvention (a first cover in the case of a voltage detector).

That is, like the related art, the current detection printed board 1 andthe voltage detection printed board 2 are disposed in the casing. Thecasing main body 300 is common to the current detection printed board 1and the voltage detection printed board 2. Then, if the currentdetection printed board 1 is fixed on the front surface of the casingmain body 300, the voltage detection printed board 2 is fixed on therear surface thereof. Accordingly, the current detection printed board 1and the voltage detection printed board 2 are accommodated in separatespaces, respectively. Therefore, there is almost no mutual interferencebetween the current detection printed board 1 and the voltage detectionprinted board 2, and detection accuracy increases.

Next, other parts than the current detector cover 301 and the voltagedetector cover 302 will be specifically described.

FIGS. 14A to 14C are diagrams of the casing main body 300. Specifically,FIG. 14A is a diagram as viewed from a side on which the currentdetection printed board 1 is fixed. FIG. 14B is a cross-sectional viewof a side surface of the casing main body 300. FIG. 14C is a diagram asviewed from a side on which the voltage detection printed board 2 isfixed.

FIGS. 15A and 15B are diagrams three-dimensionally showing the casingmain body 300. Specifically, FIG. 15A is a diagram as viewed from theside on which the current detection printed board 1 is fixed, and FIG.15B is a diagram as viewed from the side on which the voltage detectionprinted board 2.

FIGS. 16A and 16B are diagrams when the current detection printed board1 and the voltage detection printed board 2 are mounted on the casingmain body 300 in a state where the current detector cover 301 and thevoltage detector cover 302 are not mounted. Specifically, FIG. 16A is adiagram of the current detection printed board 1 side. FIG. 16B is adiagram of the voltage detection printed board 2 side.

As shown in FIGS. 14A to 16B, a through hole 303 and concave portions311, 312, 321, and 322 are provided in the casing main body 300.Accordingly, the power transmission conductor 66 and the insulator 69covering the power transmission conductor 66 pass through the casingmain body, and the current detection printed board and the voltagedetection printed board 2 are accommodated in the casing main body.Moreover, the current detection printed board 1 is accommodated on aside where the concave portions 311 and 312 are provided, and thevoltage detection printed board 2 is accommodated on a side where theconcave portions 321 and 322 are provided.

Four board fixing portions 315 are provided at four corners of theconcave portion 311, and the current detection printed board 1 is fixedto the portions. This is to allow the current detection printed board 1to float with respect to the bottom surface of the concave portion 311such that the coiled wire provided in the current detection printedboard 1 does not come into contact with the casing.

Similarly, four board fixing portions 324 are provided at four cornersof the concave portion 321 such that the voltage detection printed board2 floats with respect to the bottom surface of the concave portion 321.

For example, unlike FIGS. 3A to 3E, when the coiled wire 10 of thecurrent detection printed board 1 is not formed on the rear surfacelayer of the board, the board fixing portions 315 provided at the fourcorners of the concave portion 311 can be removed. Then, the height ofthe bottom surface of the concave portion 311 can be the same as theheight of the bottom surface of the concave portion 312. For thisreason, the structure of the casing main body 300 can be simplified.Similarly, for example, unlike FIGS. 10A to 10E, when the ring-shapedwire 30 of the voltage detection printed board 2 is not formed in therear surface layer of the board, the board fixing portions 324 providedat the four corners of the concave portion 321 can be removed, and thusthe height of the bottom surface of the concave portion 321 can be thesame as the height of the bottom surface of the concave portion 322. Forthis reason, the structure of the casing main body 300 can besimplified.

Further, on the current detection printed board 1 side of the casingmain body 300, a first shield portion 313 that shields a magnetic fluxis provided in the vicinity of the penetration hole.

Next, the current detection printed board 1 and the voltage detectionprinted board 2 will be respectively described.

(Description of Current Detection Printed Board 1)

The coiled wire 10 of the current detection printed board 1 is the sameas that of the current detection printed board 1 in FIGS. 1A to 1D, butthe output wires 21 and 22 are connected to the current conversioncircuit 51 in forms of the pattern wires. The current conversion circuit51 corresponds to the current conversion circuit 84 shown in FIG. 27.

Accordingly, unlike the current detection printed board 1 in FIG. 1, thecoiled wire 10 and the current conversion circuit 51 are provided on thesame board. Further, the output wire 52 connected to the currentconversion circuit 51 extends towards the outside of the casing througha wire opening 316. Moreover, the current conversion circuit 51 has anoutput terminal to which the output wire 52 is connected. In addition,the output wire 52 may be partially a pattern wire or may be overall awire other than the pattern wire.

In the casing main body, a second shield portion 314 is provided at acorresponding position between the coiled wire 10 of the currentdetection printed board 1 and the current conversion circuit 51. Forthis reason, the current detection printed board 1 has a shape having apartially narrower width according to the second shield portion 314.

Moreover, the current conversion circuit 51 is an example of a firstconversion circuit of the invention, and the output wire 52 is anexample of a fifth wire of the invention (a third wire in the case of acurrent detector).

(Description of Voltage Detection Printed Board 2)

The ring-shaped wire 30 of the voltage detection printed board 2 is thesame as the voltage detection printed board 2 in FIGS. 1A to 1D, but theoutput wire 40 is connected to the voltage conversion circuit 53 informs of the pattern wire. The voltage conversion circuit 53 correspondsto the voltage conversion circuit 93 in FIG. 27.

Accordingly, unlike the voltage detection printed board 2 in FIG. 1, thering-shaped wire 30 and the voltage conversion circuit 53 are providedon the same board. Further, the output wire 54 connected to the voltageconversion circuit 53 extends towards the outside of the casing througha wire opening 325. Moreover, the voltage conversion circuit 53 has anoutput terminal to which the output wire 54 is connected. In addition,the output wire 54 may be partially a pattern wire or may be overall awire other than the pattern wire.

In the casing main body, a third shield portion 323 is provided at acorresponding position between the ring-shaped wire 30 of the voltagedetection printed board 2 and the voltage conversion circuit 53. Forthis reason, the voltage detection printed board 2 has a partiallynarrower width according to the third shield portion 323.

Moreover, the voltage conversion circuit 53 is an example of a secondconversion circuit of the invention (a first conversion circuit in thecase of a voltage detector), and the output wire 54 is an example of asixth wire of the invention (a third wire in the case of a voltagedetector).

(Effects of Casing)

Next, the effects of the casing will be described.

(i) Effects of Current Detection Opening 317

FIG. 17 is a cross-sectional view showing a case where the powertransmission conductor 66 and the insulator 69 covering the powertransmission conductor 66 penetrate the current/voltage detector 3. FIG.17 shows a state where the current detector cover 301 and the voltagedetector cover 302 are mounted. Moreover, the board fixing portions 315and 324 shown in FIGS. 14A to 14C and the like are not shown. Further,the current detection printed board 1 and the voltage detection printedboard 2 are partially omitted. In addition, as shown in FIG. 17, apenetration hole, through which the power transmission conductor 66 andthe insulator 69 covering the power transmission conductor 66 passes, isprovided in the current detector cover 301 and the voltage detectorcover 302.

If a current flows in the power transmission conductor 66, a magneticflux occurs around the conductor. The magnetic flux acts on the coiledwire 10 provided in the current detection printed board 1, such that acurrent flows in the coiled wire 10. Then, the current flowing in thecoiled wire 10 is detected, thereby recognizing the current flowing inthe power transmission conductor 66. For this reason, if the powertransmission conductor 66 and the current detection printed board 1 areshielded by the conductor casing, the magnetic flux does not act on thecurrent detection printed board 1, and thus the current cannot bedetected. Accordingly, an opening 317, through which the magnetic fluxgenerated around the conductor is introduced into the casing, isprovided in the casing. The opening 317 is formed by a gap between thefirst shield portion 313 and the current detector cover 301.

(ii) Effects of Second Shield Portion 314

An electromagnetic wave is generated by an AC current flowing in thepower transmission conductor 66. Since the electromagnetic wave has aneffect on a circuit characteristic, it is necessary to prevent theelectromagnetic wave from entering the current conversion circuit 51, ifpossible. For this reason, the second shield portion 314 is provided inthe casing, thereby realizing an electromagnetic shield effect andkeeping a good circuit characteristic of the current conversion circuit51.

Moreover, the second shield portion 314 is formed by narrowing the boardwidth. This is to shield an electromagnetic wave passing through theinside of the board. That is, the reason why the second shield portion314 having a narrower board width is formed is that, when the secondshield portion 314 is provided to cover the upper portion of the board,without narrowing the board width, an electromagnetic wave passesthrough the portions of the board, and thus an electromagnetic shieldeffect becomes weak.

FIGS. 18A and 18B show an example of an application of the second shieldportion 314.

As shown in FIGS. 14A to 16B, since only with the second shield portion314 of the casing main body 300, a gap occurs in the output wires 21 and22 of the coiled wire 10, electromagnetic shield may not be sufficient.In this case, as shown in FIG. 18A, a shield portion 317 for burying thegap may be provided in the current detector cover 301. In such a manner,the gap in the output wires 21 and 22 is almost removed, and thus anelectromagnetic shield effect increases.

Further, as shown in FIG. 18B, instead of the second shield portion 314,a shield portion 318 may be provided in the current detector cover 301.

Moreover, as for the third shield portion 323 of the voltage detectionprinted board 2 side, the same one as the shield portion 317 or theshield portion 318 provided in the current detector cover 301 may beprovided in the voltage detector cover 302, thereby increasing anelectromagnetic shield effect. This is the same as FIGS. 18A and 18B,and the description thereof will be omitted.

As described above, as for the current detection and voltage detectionsides, the casing main body 300 is formed as a single body. For thisreason, as described above, current detection and voltage detection canbe performed in separate spaces, and the outputs can be converted intovoltage levels using the individual conversion circuits. Therefore,there is almost no mutual interference, and thus detection accuracy canbe improved.

(Modification of Current/Voltage Detector)

FIGS. 19A and 19B show a current/voltage detector 3 a as a modificationof the current/voltage detector 3. However, a current detector cover 301a and a voltage detector cover 302 a are not shown. In FIGS. 19A and19B, the current detection printed board 1 is as shown in FIGS. 1A to1D, and the voltage detection printed board 2 is as shown in FIGS. 9A to9D. That is, the current conversion circuit 51 is not provided in thecurrent detection printed board 1, and the voltage conversion circuit 53is not provided in the voltage detection printed board 2. A casing mainbody 300 a having a shape for the current detection printed board 1 andthe voltage detection printed board 2 is used. For this reason, theoutput of the current detection printed board 1 is output outside thecasing by output wires 25 and 26, not pattern wires. Further, the outputof the voltage detection printed board 2 is output outside the casing byan output wire 42, not a pattern wire. Moreover, the output wires 25 and26 are connected to a current conversion circuit 51 that is separatelyprovided, and the output wire 42 is connected to the voltage conversioncircuit 53 that is separately provided.

(4) Current Detector and Voltage Detector

In the above description, the current detector 310 and the voltagedetector 320 are formed as a single body. However, the invention is notlimited thereto, but the current detector 310 and the voltage detector320 may be separately provided. Here, the same reference numerals asFIGS. 12A to 12C are used.

FIG. 20 is a diagram showing an example where the current detectionprinted board 1 and the voltage detection printed board 2 areaccommodated in separate casings, thereby forming the current detector310 and the voltage detector 320 separately. As shown in FIG. 20, if thecurrent detector 310 and the voltage detector 320 are providedseparately and disposed such that both sides overlap each other, thesame effects as the current detector and the voltage detector formed asa single body can be obtained.

FIG. 21 is a diagram showing an application when the current detector310 and the voltage detector 320 are provided separately. As shown inFIG. 21, the current detector 310 and the voltage detector 320 mayoverlap each other in different directions, not in the same direction.Moreover, as shown in FIG. 21, if the penetration holes 303 provided inthe individual detectors are coaxially located, the power transmissionconductor 66 can be linear, and thus the structure can be simplified.Further, ease of assembling can be realized.

Although an example where the detector is provided at the input terminal63 a of the impedance matching device has been described in the abovedescription, the invention is not limited thereto. For example, thedetector may be provided at an output terminal of the high-frequencypower supply device 61 or may be provided at the output terminal 63 b ofthe impedance matching device. Moreover, as described above, there is adifference in current and voltage at the input terminal 63 a and theoutput terminal 63 b (the same as the input terminal of the load 65) ofthe impedance matching device. For this reason, when the detector isprovided at the output terminal 63 b of the impedance matching device orthe input terminal of the load 65, in order to extend an insulationdistance, it is preferable to use a power transmission conductor 68having a large diameter or an insulator 69 covering the periphery of thepower transmission conductor 68 in consideration of the difference.Further, the detector may be used for other systems other than thehigh-frequency power supply system.

Although a case where the current detector 310 is disposed near theinput and the voltage detector 320 is disposed at the back of thecurrent detector 310 has been described in the above description, asshown in FIG. 22, the voltage detector 320 may be disposed near theinput.

Although an example where the current detector 310 and the voltagedetector are used together has been described in the above description,either the current detector 310 or the voltage may be used.

(5) Fixing Method

When the outer diameter of the insulator 69 and the inner diameter ofthe penetration hole provided in the casing main body 300 aresubstantially consistent with each other, the insulator 69 and thecurrent/voltage detector 3 can be fixed. However, actually, theinsulator 69 having an outer diameter smaller than the inner diameter ofthe penetration hole may be used. In this case, a gap occurs between theinsulator 69 and a casing main body 305. As such, if the gap exists,when the power transmission conductor 66 and the current/voltagedetector 3 are mounted on the impedance matching device 63, the relativeposition therebetween may not be constant according to mounting devices.In this case, when a plurality of devices are formed, a variation indetection value of the individual devices occurs. For this reason, whenthe gap is large, it is preferable to keep the relative position betweenthe power transmission conductor 66 and the current/voltage detector 3constant.

FIG. 23 is a diagram showing a fixing method of the insulator 69. Asshown in FIG. 23, a concave portion is provided in the insulator 69, andthe current detector cover 301 and the voltage detector cover 302 arefitted into the concave portion. With this configuration, the insulator69 can be fixed by the current detector cover 301 and the voltagedetector cover 302. Then, even though the outer diameter of theinsulator 69 is smaller than the inner diameter of the penetration hole303, the relative position between the power transmission conductor 66,and the current detection printed board 1 and the voltage detectionprinted board 2 can be substantially kept constant.

As described in FIG. 20 and the like, the fixing method can be appliedto a case where the current detector 310 and the voltage detector 320are provided separately.

FIG. 24 is a diagram showing a fixing method of the insulator 69 whenonly the current detector 310 is used separately. Moreover, in FIG. 24,the casing main body of the current detector 310 is used as the casingmain body 305. Further, in case of the voltage detector 320, the samemethod can also be adopted. Here, the description thereof will beomitted.

As shown in FIG. 20, when the current detector 310 and the voltagedetector 320 are double-barreled, like FIG. 23, the insulator 69 can befixed by the current detector cover 301 and the voltage detector cover302. However, when either the current detector 301 or the voltagedetector 302 is used, either an upper cover or a lower cover does notexist (as viewed from the paper). Then, the insulator 69 may not bestably fixed. In this case, as shown in FIG. 24, in order to stabilizethe insulator, a mounting part 306 for fixing the insulator 69 may beprovided at the lower portion of the casing main body 305 (as viewedfrom the paper). The mounting part 306 is fitted into the concaveportion provided in the insulator 69 and is mounted on the casing mainbody 305 by beads or the like (not shown). Of course, the invention isnot limited to the examples shown in FIGS. 23 and 24. For example, theshape of the mounting part 306 may be changed.

FIG. 25 is a diagram showing a case where the sizes of the powertransmission conductor 66 and the insulator 69 are suited to the size ofthe current/voltage detector in the current/voltage detector 3 shown inFIG. 23. Moreover, in the example of FIG. 24, the same method can alsobe adopted. Here, the description thereof will be omitted.

Like FIG. 23, when the insulator 39 is fixed to the current/voltagedetector 3, in order to improve maintenance, as shown in FIG. 25, thesizes of the power transmission conductor 66 and the insulator 69 may besuited to the size of the current/voltage detector 3, such that thepower transmission conductor 66 and the insulator 69 can be removed fromthe current/voltage detector 3. With this configuration, maintenance canbe improved. Moreover, in FIG. 25, though not shown, a connectionportion for connection to another conductor is provided in the powertransmission conductor 66. Moreover, the current detector cover 301, thevoltage detector cover 302, and the mounting part 306 of FIGS. 23 to 25are an example of a fixing unit of the invention.

Although an example where high-frequency power having a frequency (forexample, a frequency of hundreds kHz or more) of a radio frequency bandis used has been described in the above description, AC power having afrequency lower than the frequency of the radio frequency band may beused. Meanwhile, in case of the high frequency, such as the frequency ofthe radio frequency band, it is necessary to shield the electromagneticwave using the second shield portion 314 and the third shield portion323 in the casing. Accordingly, when the frequency of AC power is lowand an influence of the electromagnetic wave is negligible, the secondshield portion 314 and the fourth shield portion 323 may not beprovided. Besides, since characteristics are different according to thefrequencies to be used, it is preferable to use a casing suitable forthe characteristic.

Although a case where the power transmission conductors 66 and 68 are acylindrical copper rod, that is, has a circular shape in section hasbeen described in the above description, the invention is not limitedthereto. For example, a conductor having an elliptical shape or arectangular shape in section may be used. Further, although a case wherethe penetration hole 101 of the current detection printed board 1 andthe penetration hole 201 of the voltage detection printed board 2 have acircular shape has been described, the invention is not limited thereto.For example, an elliptical shape or a rectangular shape may be used.

As described above, there exist various kinds of the current detectionprinted board, the voltage detection printed board, and the detectorsusing the same. Therefore, other combinations than those described abovecan be made.

1. A voltage detector comprising: a voltage detection printed board including: a board having a penetration hole that penetrates the board; a first pattern wire formed at a periphery of the penetration hole; a second pattern wire formed at the periphery of the penetration hole; and a plurality of through holes that penetrate the board between the first and second pattern wires; and a conductive casing in which the voltage detection printed board is fixed, wherein, when a conductor, in which an AC voltage is generated, is disposed to pass through the penetration hole, the pattern wires act with the conductor to function as electrodes of a capacitor.
 2. The voltage detector according to claim 1, wherein the first pattern wire is formed on a top conductive layer of the board, and the second pattern wire is formed on a bottom conductive layer of the board.
 3. The voltage detector according to claim 1, wherein the board comprises a plurality of layers, and the first and second pattern wires are formed between layers of the board.
 4. The voltage detector according to claim 1, wherein the penetration hole has a circular shape, and the pattern wires are formed in a circular shape at the periphery of the penetration hole.
 5. The voltage detector according to claim 1, wherein the AC voltage is an AC voltage having a frequency of a radio frequency band. 